Proteins are used in diverse applications going from food to non-food applications. Currently these proteins are mainly available in a dried powder form.
Fish farming is an increasingly thriving industry in many parts of the world. Fish feed for farmed fish is usually produced in the form of pellets.
WO98/49904, relates to the formation of porous feed pellets by extrusion, drying, and absorbing oil into said pellets by vacuum coating. In addition, extruded fish feed is very delicate and must be transported using specialised systems to minimise damage.
An alternative method (WO97/22265) suggested coating the extrusion formed pellets with water soluble starches. The use of starches in the composition is uneconomical insofar as they are not (or only poorly) digested by fish. They therefore have no nutritional benefit and are considered to amount to wasted expenditure.
EP 0 711 510 relates to a process for the production of fermenting materials. In an intermediate stage, pellets of dried gluten products are made and the moisture content upon granulation is within the range of 12 to 18%. It is clearly demonstrated that the possibility of forming pellets is dependent upon moisture content and denaturation of the proteins.
U.S. Pat. No. 5,102,671 relates to a process for the manufacture of feed pellets. The wheat gluten is added only in the order of one or three percent.
EP 0 838 159 describes a method for the size reduction of wet gluten. The method applies wet gluten for size reduction. The granules are stored at temperatures below 0° C.
EP 1 527 700 describes fish feed and process for preparing the same. The composition comprises at maximum 75% gluten and beyond the proteins dehulled oilseeds are present.
U.S. Pat. No. 6,309,680 relates to a pelletization process wherein the wheat gluten is denatured.
There is therefore a clear need for an alternative and more economical method of producing pellets consisting of dried compressed proteins, and more in particular still comprising vital wheat gluten. The present invention provides such a method.